智能化网络考试监控系统开发

近年来随着高等教育事业的快速发展,为了节约教育成本、提高教学质量和教育的信息化程度,网络化、无纸化考试在高校得到了快速推广。但由于计算机网络是一个开放的系统,考试中电子文档资料可以十分隐秘地被复制和在学生间传递,造成很多严重的作弊行为。如何防范当前网络考试中考生的作弊行为及保障考试结果的公平性成为了急需解决的重要问题。本论文所开发的智能化网络考试监控系统克服了现有考试监控系统的不足,将各种网络考试实时监控信息机地结合在一起,实现了作弊行为检测、作弊行为发现及作弊行为报警三位一体的立体化管理。同时,所开发的网络考试监控系统独立于现有各网络考试系统,在不影响现有考试系统正常工作的情况下,实现了考试作弊行为的有效监控,使其具有良好的可推广性及可维护性。     

Cheating behaviours,the Internet and Education undergraduate students

This paper describes an illuminative small‐scale study that piloted an initial survey instrument intended to investigate correspondences between 47 undergraduate Education final year students' use of information and communications technology (ICT), including the Internet, and – within the context of their adoption of tactics intended to impress lecturers or to exploit the hidden curriculum – students' engagement in cheating behaviours such as plagiarism. The study disclosed that 0.23 of the sample had reported single instances of cheating behaviours and that 0.21 of the sample had reported multiple instances of cheating behaviours. Analysis of data discerned correspondences between these cheating behaviours and personal factors. However, indicators of ICT capability and the Internet did not correlate significantly with cheating behaviours. Those students who had reported multiple instances of cheating behaviours were found to rate their ICT capabilities higher than their peers but had a tendency to report less frequent use of the Internet for coursework. Inferences are tentatively drawn for further research and for academic practices.     

A social-cognitive approach to online game cheating

Drawing upon social cognitive theory, the present study constructed a conceptual model to provide an in-depth understanding of the key psychosocial factors shaping the cheating behavior in online multiplayer games. An online survey approach and structural equation modeling were adopted to investigate the hypothesized relationships and to assess the fitness of the model. The findings of this study provided support for the research model and the social cognitive theory perspective on game cheating behavior. The cheating behavior was found to be influenced by both external and self-generated factors. Specifically, individual gamers’ social environment (peer influence), their own attitude towards game cheating, and evaluation of cheating outcomes played an important role in shaping this problematic behavior in online games. Game cheating self-efficacy was interestingly found to be an insignificant factor for the game cheating behavior. The study fills a gap in the current literature on games and cheating, specifically on the social cognitive mechanisms of the cheating behavior in online multiplayer games.     

面向多维稀疏数据仓库的欺诈销售行为挖掘

分销渠道系统中,产品制造商会分配给销售额较大的分销商更多返点利润鼓励销售,而分销商之间可能会联合起来将多个分销商的销售业绩累计在其中一个分销商上,获取高额利润,这种商业欺诈行为被称为挂单或窜货.由于数据中大量正常极值点的存在,使得传统异常探测算法很难区分正常极值和由挂单导致的异常极值;另外,多维销售数据本身就存在的稀疏性导致多维数据异常探测算法无法有效运行.为了克服上述问题,将人工智能和数据库技术结合起来,提出了基于分割率的特征提取方法和基于张量重构的挂单行为挖掘算法.同时,由于分销商之间存在多种挂单行为,设计了基于挂单模式偏序格的特征提取方法来对销售数据集中存在的挂单行为进行分类.在合成数据的实验中,所提出的挂单点挖掘算法能达到65%的平均AUC值,而传统特征提取方法仅达到36%和30%的平均AUC值.在真实数据上的实验结果表明,挂单行为探测方法能区分正常销售极值和挂单行为产生的异常极值.     

一种基于概率统计方法的P2P系统信任评价模型

现有的P2P系统信任评价模型正面临着两种恶意节点的攻击行为--策略性欺骗和不诚实推荐,严重影响了模型计算节点信任评价的准确性和有效性.针对现有模型存在的不足,提出了一种基于概率统计方法的信任评价模型.该模型借鉴人类社会中主观信任关系的概念,依据直接经验和反馈信息,利用概率统计方法分别计算节点的直接信任和推荐信任,并通过区分直接经验的重要程度,区分反馈信息及其推荐者的可信度,提高信任评价模型的有效性.仿真实验分析说明,与已有的信任评价模型相比,该模型能够更有效地抑制策略性欺骗和不诚实推荐的威胁,特别是复杂的协同作弊方式对系统的攻击.     

Is cheating a human function? The roles of presence,state hostility,and enjoyment in an unfair video game

In sports and board games, when an opponent cheats, the other players typically greet it with disdain, anger, and disengagement. However, work has yet to fully address the role of the computer cheating in video games. In this study, participants played either a cheating or a non-cheating version of a modified open-source tower-defense game. Results indicate that when a computer competitor cheats, players perceive the opponent as being more human. Cheating also increases player aggravation and presence, but does not affect enjoyment of the experience. Additionally, players that firmly believed that their opponent was controlled by the computer exhibited significantly less state hostility compared to players that were less certain of the nature of their competitor. Game designers can integrate subtle levels of cheating into computer opponents without any real negative responses from the players. The results indicate that minor levels of cheating might also increase player engagement with video games.     

Private Camera Conversation: a new method for eliciting user responses?

Abstract

This paper discusses a new method called Private Camera Conversation. This method can be used to elicit user opinions on various subjects like their use of products. Initial impressions of the method are given on the basis of three small studies in which the method was employed. The method has not yet been validated and compared with existing human factors methods. This study reports the first findings of the application of the method. With Private Camera Conversation people are invited to talk about a particular topic in private to a video camera. The participants themselves decide when they want to start and when they want to stop the recording session. Initial impressions arc that the method has potential benefits for eliciting rich and useful responses even with respect to ‘personal’ issues. The Private Camera Conversation method seems particularly suitable for obtaining information about the social context in which products are used and about qualitative aspects of product use. The method is inviting and entertaining for participants and easy and effective to carry out. Optimal exploitation of the method has to be realized through further development. We hope this article will be a catalyst for further research.     

A cheating prevention scheme for binary visual cryptography with homogeneous secret images

In 1995, Naor and Shamir proposed the k-out-of-n visual cryptography scheme such that only more than or equal to k participants can visually recover the secret through superimposing their transparencies. Visual cryptography schemes have been extensively investigated since their invention and extended to numerous applications such as visual authentication and identification, steganography, and image encryption. In 2006, Horng et al. proposed that cheating is possible where some participants can deceive the remaining participants by delivering forged transparencies. Meanwhile, Horng et al. also proposed two cheating prevention schemes. One scheme, however, requires extra verification transparencies and the other needs larger transparencies. In other words, compared to visual cryptography, both schemes burden each participant with an additional problem of transparency management. In this paper, a more secure scheme is given to solve the cheating problem without extra burdens by adopting multiple distinct secret images. Moreover, for sharing these secret images simultaneously, the share construction method of visual cryptography is redesigned and extended by generic algorithms. Finally, the results of the experiment and security analysis show that not only the proposed scheme is more secure in comparison with the two previous cheating prevention schemes in the literature, but extra burdens are also eliminated.     

Time to stabilisation of the cervical spine when supported by a pillow in side lying

Currently, there is little information to guide consumers, retailers and health professionals about the length of time it takes for the cervical spine to stabilise when resting on a pillow. The aim of this study was to determine the time required to achieve stabilisation of the cervical spine when supported by a polyester pillow and innerspring mattress in side lying. Twenty-four asymptomatic females rested in a standardised side lying position during the capture of 3D data from markers placed over cervical landmarks. Time to stabilisation was assessed for each axis, each landmark and globally for each participant. A large variation in global stabilisation times was identified between participants; however, 70.8% of participants had stabilised by 15 min or earlier. Fifteen minutes is the best estimate of the time to stabilisation of the cervical spine for young females in a side lying position when resting on a polyester pillow.

Practitioner Summary: This study aimed to determine the time required to achieve stabilisation of the cervical spine when supported by a polyester pillow and innerspring mattress in side lying. Through a laboratory study using 3D VICON^® motion analysis technology, we identified that 70.8% of participants had stabilised by 15 min.     

大型标准化考试的防作弊方法

在大型标准化考试中利用高科技通讯工具作弊的现象有上升趋势.为保证考试结果的公平性,分析了标准化考试中利用通讯工具作弊的主要特征,提出了试卷类型采用条形码的防高科技通讯手段作弊的方法,以从技术层面上防范此类作弊行为.     

基于密钥协商的门限多秘密共享方案

为使攻击者在骗取所有共享者的子秘密时无法恢复秘密,提出一种基于密钥协商的门限多秘密共享方案。该方案使系统内的成员相互制约,子秘密由共享者自己选取,且可重复使用,系统不需要秘密信道。共享者可以方便地动态加入或离开系统,且所有秘密能一次性恢复。     

博弈论框架下P2P实时流的合作模型研究

针对P2P实时流环境中出现的“搭便车”和“公共悲剧”问题,提出一种博弈论框架下的激励合作模型。分析该模型达到Nash均衡和Pareto最优状态下对应的比例公平策略优化。并考虑存在欺骗行为的情况,研究对应的节点行为策略。理论分析表明,该模型能够刺激节点合作,并且对节点的欺骗行为具有抑制作用。     

基于信任向量的P2P信任机制

针对现有P2P信任机制不能有效地检测和惩罚短期内反复建立信任然后进行恶意攻击的摇摆节点,本文提出了基于信任向量和时间窗口的信任机制,用信任向量记录节点的交易信息,用时间窗口收集最近一段时间内交易的记录,提高了信任评估的准确性和动态性。仿真实验表明,与已有的信任机制相比,该机制能够有效处理动态恶意节点行为。     

Permanently online – Permanently connected: Explorations into university students’ use of social media and mobile smart devices

BackgroundWith the availability of mobile smart devices, many adolescents have developed the habit of being online and connected with other users almost all the time.ObjectiveThe aim of this paper is to provide a definition of being permanently online (PO) and permanently connected (PC) and to explore students’ current PO/PC behaviors.MethodsAn online survey was conducted with 178 university students in Germany to explore the intensity of their PO/PC behaviors in various social situations, the differences in being PO and being PC, students’ feelings about a possible loss of Internet access, and their online responding behaviors. We also shed some light on the associations between being PO/PC and various aspects of well-being, as well as between PO/PC and demographics and lifestyle.ResultsSmart device usage behaviors at night and behaviors in various social situations during the day indicate that PO and PC behaviors are occurring frequently. The results show that being connected to others (PC) seems to be more relevant to the participants than browsing the web (PO). Moreover, the participants expressed strong emotional responses about a temporary loss of Internet access. Coping behaviors in response to increasing number of incoming messages and permanent availability are reported.ConclusionThis exploratory study demonstrates the relevance of the concepts of being PO and PC to students, and points out further research gaps.     

搜索引擎优化的作弊与防范

随着信息技术的飞速发展,人们越来越多的通过搜索引擎获取信息。快速增长的互联网信息在提供丰富的资源的同时也催生了大量的搜索引擎作弊的行为。本文先是通过对搜索引擎优化的作弊手段进行分析进而提出防范作弊的几种方法。     

基于双线性对的动态广义秘密共享方案

利用双线性对构建了一个具有广义接入结构的高效的多秘密共享方案。每个参与者的私钥作为其子秘密,秘密分发者和参与者之间无需维护安全信道。方案能够动态地增加或删除成员,而其他成员无需重新选择子秘密,减少了方案实施的代价。分析表明,该方案是正确的,能防止参与者之间相互欺骗攻击,且参与者的子秘密可复用。     

对基于单向函数的He-Dawson多步骤秘密共享方案的改进

在(t,n)门限秘密共享方案中,有n个参与者,至少t个参与者拿出自己的子秘密就能够同时重构m个秘密.He-Dawson提出了一个基于单向函数的多步骤秘密共享方案.但是他们的方案是一次方案而且不能抵抗合谋攻击.每个参与者的子秘密由参与者自己选取,所以不存在秘密分发者的欺骗.并且每个参与者能够验证其他合作者的欺骗.每个参与者选取的子秘密可以复用.并且组秘密可以以任意顺序重构.此方案还能够抵抗合谋攻击.本方案的安全是基于Shamir门限方案和RSA密钥体制.     

一种动态安全的多重密钥门限共享方案

给出了一种动态安全的多重密钥门限共享方案,在该方案中成员可以安全有效地共享多个密钥,具有动态安全性,能够在不改变共享秘密的前提下,周期性更新成员的子密钥,攻击者需要在更新周期内完成攻击过程,任意t个授权成员联合在任意时刻都可以恢复共享密钥,采用可验证的秘密共享方法能够有效地抵御管理者欺骗和成员欺骗,最后证明了方案的正确性和机密性。     

防范电子商务信用骗取的种群共存模型

通过一个简化的演化博弈模型,发现由于信用体系存在技术上或规则上的潜在漏洞,以及交易者是自利理性的,电子商务信用骗取行为的出现不可避免。为此构建种群共存模型,分析信用评级与交易者之间不同关系的稳定演化结果,提出建立一种与交易者“独立共存”的新型信用体系以有效防范信用骗取。仿真实验很好地支持了上述结论。     

Internet pornography exposure and risky sexual behavior among adult males in the United States

Sexually transmitted infections (STIs) continue to pose a threat to the public health in the United States. Many sexual behaviors increase an individual’s risk of STI contraction. Chief among these are having unprotected sex, having sex with multiple partners, and either paying for sex or having sex for pay. The present study used General Social Survey (GSS) data from 2000, 2002, and 2004 to explore the association between exposure to internet pornography and these STI risk behaviors among adult US males. After controlling for demographic and individual difference covariates, internet pornography consumption was positively associated with having sex with multiple partners, engaging in paid sex, and having had extramarital sex. Internet pornography consumption was unrelated to having unprotected sex. Subsequent GSSs have not asked participants about exposure to internet pornography. As the GSS is the only ongoing, full-probability, national survey assessing social beliefs and behaviors, the present report provides unique insight into the risky sexual behavior patterns of adult male internet pornography consumers in the United States.